When President Trump’s budget plan hit the Internet at midnight Wednesday, Virginia and Maryland environmental activists could not believe what they saw. A total elimination of the Chesapeake Bay program seemed impossible to them, considering the success of the federally funded six-state partnership over the past 15 years.

So the activists got to work, along with elected officials from throughout the region, planning rallies, firing off dire warnings and promising to petition theRepublican majority in Congress, which has the ultimate say over whether to defund bay restoration.

“We will fight with every fiber in our bodies” to see the funding maintained, Chesapeake Bay Foundation President William C. Baker said on Thursday. “This just makes no sense. We are in disbelief. The EPA’s role in this cleanup is nothing less than fundamental.”

The $73 million-a-year Environmental Protection Agency program has united Virginia, Maryland, Delaware, West Virginia, Pennsylvania, New York and the District of Columbia in working to reduce pollution levels in the bay.

(Video: Jenny Starrs/Photo: Jabin Botsford/The Washington Post)

Cutting off funding, bipartisan supporters of the cleanup say, would threaten multibillion dollar tourism, recreation and commercial industries and could reverse strides in water quality that sustain fishing, boating and crabbing in the largest estuary in North America.

Last year, the Chesapeake Bay program funneled about $9.3 million to Virginia, $9 million to Maryland and $2.6 million to the District for state, local and nonprofit projects and staff. The remainder went to the other state and local governments, nonprofits and schools.

The money pays for such basics as upgrades to deteriorating sewer facilities and fences to limit chemical runoff from farms — efforts that have resulted in clearer water and the return of sea grasses critical to the survival of fish.

Virginia Gov. Terry McAuliffe (D) said the elimination of EPA cleanup funds is the latest Trump proposal that would wreak havoc on the state. From the entry ban suspending the admission of new refugees to a health-care bill that would leave hundreds of thousands of residents uninsured, he said in an interview, “this man is a one-man wrecking crew to the economy of Virginia.”

Maryland Gov. Larry Hogan (R) declined to join the chorus of opposition to Trump’s budget proposal, noting that it is up to Congress to pass a budget and that the cuts outlined by the administration may never come to pass.

But his spokesman said Friday that Hogan “has invested more than $3 billion in efforts to protect and restore the Chesapeake Bay and will remain a fierce advocate going forward. He will always fight to project our state’s most important natural asset.”

Advocates say that a restored bay would generate a $130 billion economic boon to the watershed states by 2025, the end of the current phase of the program.

The 18 million residents who live in the watershed include “old guys who have been fishing in the bay for years,” and a lot of them voted for the president, said McAuliffe, who is chairman of a six-state council that oversees the bay. “I don’t think he has any idea what he has stepped into on this one.”

Pushback came not only from predictable Trump foes such as McAuliffe. Four House Republicans — Virginia Reps. Rob Wittman, Barbara Comstock and Scott W. Taylor and Maryland Rep. Andy Harris — last week reiterated their opposition to cleanup cuts.

And an aide to Rep. Bob Goodlatte (R-Va.), the senior Republican in the Virginia delegation and the powerful chairman of the House Judiciary Committee, said the congressman also has concerns about eliminating the Chesapeake Bay program.

In an interview in Wittman’s Capitol Hill office, which is painted aqua and decorated with blue fish and trout he caught in the bay, Wittman credited the EPA program with renewing oyster, crab and fish populations — and said he will fight for federal funding to stay at current levels.

“I think it would be a big mistake to walk away from this at the magnitude that this has and still expect that we’re going to make the same progress in cleaning up the bay,” said Wittman, who lives on a Chesapeake tributary and is the father of a waterman.

Not everyone was alarmed by the White House proposal. Rep. H. Morgan Griffith (R-Va.) cheered the possibility of slashing the EPA’s bottom line. Trump’s plan would cut 31 percent of the agency’s budget and 3,200 positions.

“I am hopeful that the cuts will come to the out-of-control regulatory divisions of the EPA . . . while preserving their core function of helping communities preserve clean water,” he said in a statement Friday, noting that he had not yet reviewed specific cuts.

Griffith represents a rural southwest Virginia district — part of which extends into the Chesapeake watershed. Earlier this year he spearheaded the revival of a rule allowing lawmakers to drop the pay of individual federal workers to as little as $1.

But for bay advocates who were wary of the appointment of EPA Administrator Scott Pruitt, the budget was confirmation of their worst fears.

The lawsuit failed. And at his confirmation hearing in January, under questioning by Sen. Benjamin L. Cardin (D-Md.), Pruitt said the bay restoration partnership “should be commended and celebrated.”

Still, distrust of Pruitt has lingered.

“It’s not what they say, it’s what they do. And this is what they’re trying to do,” Russ Baxter, Virginia’s deputy secretary of natural resources for the bay, said Thursday, adding that Virginia agencies already struggle to balance their budgets and cannot afford to cover the federal share of the bay cleanup if the program evaporates.

In Virginia, the pushback to Trump’s budget proposal was swift. Conservation groups and state lawmakers on Saturday joined McAuliffe’s wife, Dorothy, and bay advocate Pam Northam — wife of Lt. Gov. Ralph Northam, who is running for governor — to protest the proposed cut at a rally by a Williamsburg creek that flows into the bay.

Virginia Democrats on Friday called on Trump to forgo weekends at his Palm Beach resort, Mar-a-Lago, and use the savings to taxpayers to cover the bay budget. That same day, Sen. Chris Van Hollen (D-Md.), who sits on the Senate Appropriations Committee, joined Cardin, Virginia Sens. Mark R. Warner and Tim Kaine, and other Democratic senators from watershed states in a letter opposing the cuts.

Rep. Don Beyer (D-Va.), who took part in a rally outside the EPA on Wednesday, said the lobbying strategy involves “being as noisy as we can through whatever means we can.”